1. Field of the Invention
The present invention relates to excavator buckets. More specifically, the invention is directed to a variable width backhoe bucket for earth digging machines. Still more specifically, the invention is directed to a variable width backhoe bucket for digging trenches of different widths without changing the backhoe bucket.
2. Description of the Related Art
A backhoe is the main tool found, for example, on a Caterpillar™ backhoe excavator. By way of analogy, the backhoe is an extremely powerful version of human arm or finger, and has three segments: a boom attached to a stick, which in turn is attached to a backhoe bucket; this arrangement is somewhat akin to the human arm which is made of three segments: an upper arm attached to a forearm, which in turn is attached to a hand. Three joints, comparable to a person's wrist, elbow and shoulder, connect the backhoe segments. The backhoe moves in a similar way to a person's arm but movement is driven by a hydraulic system rather than by dedicated muscles. In, for example, a Caterpillar™ backhoe, the boom is bent upward to make it easier to dig with obstacles in the way. This design also provides extra space for the backhoe bucket when the operator curls the backhoe bucket inwards with a full load.
The backhoe is used for various tasks such as digging trenches. The backhoe bucket is typically used to dig trenches of a specific width such as a two-foot (2′) and three-foot (3′) wide ditches. To dig a different width trench the conventional backhoe bucket is decoupled from the backhoe stick and swapped for another backhoe bucket with a different width. Swapping backhoe buckets is time consuming and lowers productivity. Thus, there is a need for a variable backhoe bucket that can be used to dig trenches of different width, such as two foot (2′) and three foot (3′) wide trenches, without requiring a change of bucket.
U.S. Pat. No. 5,918,390 issued Jul. 6, 1999 to Ruff, describes a bucket that consists of three shells, which are movable relative to each other and constrainedly guided towards each other. The width of the bucket is adjusted between a minimum value and a maximum value. At least two double scissors systems controllably adjust the width of the bucket. In at least one part of the '390 patent a hydraulic system is used to power the scissor system. Such scissors systems add complexity and maintain and may be prone to mechanical jamming. Thus, there is a need for an adjustable width backhoe bucket that is scissor system free.
U.S. Pat. No. 4,208,814 issued Jun. 24, 1980 to Stone, describes an extension device for an excavating bucket for increasing the cutting width and capacity of the bucket. The '814 device includes a container of generally the same cross-sectional configuration as the bucket and having attachment means for removably attaching the device on the side of the bucket and cutting edges and tines for cutting and tearing through the soil. The '814 device must be attached by an operator to the side of main excavating bucket and thereby having a deleterious impact on productivity. Specifically, working time is lost while attaching the '814 device to the main bucket. Thus, the '814 device explicitly does not solve the problem of digging variable width trenches without spending to change the digging configuration of the backhoe bucket.
European Pat. Doc. No. EP0435796 published 1991 Jul. 3 to Suau (FR), describes a bucket for an earth moving or excavation machine. The '796 bucket comprises a central section that comprises a curved bottom comprising, inside and outside metal sheets. The '796 bucket further comprises lateral sections which are substantially symmetrical with respect to a longitudinal median plane within the '796 bucket; each of the lateral sections comprises a curved lateral bottom having an inside lateral metal sheet and an outside lateral metal sheet that are joined together by two cross-pieces.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus a variable width backhoe bucket solving the aforementioned problems is desired.